Compressor unit



Feb.- 28, 1939. w PATTERSON y 2,148,638

COMPRESSOR UNIT Filled Nov. 19, 1955 .58 v ATTORNEY Patentedi'Feb. 28, 1939 November 19, 1935, No. 50,510

k'.'l'his invention relates to pump structures. and particularly pertains to a compressor unit especially adapted lfor use in connection withcounterbalance mechanism of well pump structures.

l In the operation of deep well pumps, and particularly those embodying the use' of a fluid counterbalance, as is disclosed in my co-pending application entitledWell pump construction, filed concurrently herewith, it is necessary tofprovide rcompressor means which will act to maintain 'fluid within a receiving tank at a substantially constant pressure. It is desirable to provide a compressor structure of the reciprocating type fitted with adjustable means whereby a predetermined pressure in a receiving tank may be maintained,

even though its reciprocating stroke is uniform as to length and piston displacement. It is the principal objectof the present invention to provide. a` compressor of the reciprocating type having a constant length of stroke and which structure may be so adjusted as to insurethat a desired iiuid pressure-will be exerted by the piston to maintain a constantiluid pressure within a receiving` tank with which the structure constant- I ly communicates without the use of regulatingA valves, governors, or .other control means for this ple in the accompanying drawing in which:

Figure 1 is a view in side elevation showing the application of the 'present invention to a pump structure.

Figure 2 is an enlarged view in vertical section and elevation showing the pump unit as seen on the line 2-2 of Fig. l, and particularly 'disclosing the compression space adjusting means.

on the line 3 3 of Fig. 2 and shows the connections provided between the opposite' ends of the pump cylinder whereby the pump may be compounded.. z 'l Fig. 4 is a view in ltransverse section as seen on the line Hof Fig. 2 shows the relative ar- Fig.'3 is a view through the pump unit as seen rangement of the inlet and outlet connections of the cylinder.

Referring more particularly to the drawing, I 0 indicates the sub-frame. of a pumping 1mit of the type with which the present invention may be 5 jconcerned. Carried by this sub-frame is a base unit which includes areceiving tank I I and structural frame members I2 rigidly connected therewith. Mounted upon the base unit is a power unit I3 which includes a drivingvmeans and gearA 10 reduction lneans'thfugh which a shaft Il may be driven. Secured upon the shaft I I is a crank disc. I5 from the face of which a crank pin IB projects. Engaging the crank pin is a connect- 'ing rod I1, the upper end of which connects to a 15 pivot Il carried by the cross head ofY a rocking. beam I9.l The beam I! isy pivoted forvertical swinging movement upon a fulcrum shaft 20. The fulcrum shaft 20 is carried a't the upper end of vertical posts 2l which extend downward1y'20 upon the opposite sides of the base structure and areconnected with the sub-frame III by bolts 22 which engage an end shoe bolted to the posts 2|. The outer free end of the rocking beam I9 carries a horse head 23 formed with a segment 24 over which the reins 25 of a pump polish rod are led. Rocking beam cushion and counterbalance means are provided and disposed between the free end of the rocking beam and the connecting rod i1 by whichpower is applied to the beam. This cushioning and counterbalancingv means i comprises a bracket 28 pivQted on a shaft 2I carried by the rocking beam. Aqcylinder 28 is secured to thebracket 26 and depends therefrom. Mounted within the cylinder L28 is a piston 29 35 which is carried` at the upper end of a tubular piston rod Il, said rod extending from 'the' bottom of the cylinder. The lower end of this rod is iitted with a cross shaft 3| carried in bearings 32. The oros shaft is also tubular and is 'con- 40 necd to a conduit u which leads from the cross shaft to thc air receiving tank vI I. Avalve il controls the ow of fluid to and fromthe con- A tainer Il through the conduit. I'hus the down ,stroke of the rocking` beam Ig as brought about 15 by vrotation of the crank disc I 5 and the weight of the pump rods in the well will be resisted by compressed iluid between the cylinder'head,28' and the piston 29. 0n the upload stroke the rock- 50 ing beam'will be actuated by the rotation of the crank disc, its crank pin I6, and the connecting rods l1.- This force will be augmented by the pressure ofthe fluid within the receiving tank I I,

by reason of its being `in unrestricted communcation with the compression space in cylinder 28, the piston 29, and the piston rod 30;

In connection with a pumping unit of the type previously described, a compressor unit' of the type shown particularly in Figs. 2 and 3 is desirable for the reason that such astructure can act incidental to the operation of the oscillating rocking beam to maintain the pressure of the fluid within the receiver constant. This is accomplished by the compressor unit generally indicated at in the drawing, and shown as mounted upon the base unit. The compressor unit 35 comprises a cylinder 36 which is formed with a closed head 31 at its lower end, the cylinder being secured to the base unit by a footing member 38. iitted with a packing gland 39 through which a piston rod 40 reciprocates. Attention is dii ected to the fact that this gland is of considerable length and acts to prevent the piston rodfrom being laterally displaced as it reciprocates. Mounted on the lower end of the piston rod 4B is av piston 4|. Mounted at the upper end of the piston rod 4|] is a cross head 42 fitted with trunnions 43 which are rotatably disposed within bearings at the lower ends of a pair of pitman rods 44. The upper ends `of these rods are secured to the rocking beam |9-by pivots 45. The cross head carries an adjustable sleeve 46 which is threaded through the cross head and has a central bore to'receive the piston rod 4|). A nut 41 is mounted upon the sleeve and adjustabiy locks the sleeve'in a desired position. Lock collars 48 are pinned on the upperend of the piston rod 4B by shear pins 49 which may be sheared in the case of excess strain acting upon the piston y 4|. It will also be -seen that by the adjustment afforded by the sleeve 46 the piston rod may be shifted so that the piston will occupy a. diierent stroke position within the cylinder. This piston and the'cylinder forming the compressor act in accordance with the well known isothermolcompression formula in which:

Vz Under this formula the piston when adjusted will act to change the compression ratio, as for example:

By this arrangement it is possible to adjust the piston within the cylinder to obtain any desired pressure from the compression uid and to insure that 'this will be maintained when in constantcommunication with the air receiver into which the uid is injected.

,ths shown in Fig. 2 of the drawing an air inlet 50 communicates with a check valve 5| -through which fluid may be drawn into the portion of the cylinder below the piston 4|. Anair outlet 52 is tted with acheck valvel 53 and supplies air through a pipe 54t0 the receiving tank: Il. A valve 55 is interposed in this line as well as a 7 pressure gauge 55' said valve 55 beinglocated between the gauge 55' and tank so that, by closing valve55, the pressure of air developed lby the adjusted air pump -will at once appear on the gauge 55. The piston 4| divides a cylinder 36 into an upper compression space 561 and a lower compression space 51. The lower end of the lower space is dened by the end wall 31. The upper ,end of the upper `space is `dened by an end wall 58 of the packing head 39. A pipe sa extends through the wall or the cylinder 36 The upper end of the cylinder is adjacent to the end Wall 58. As here shown a T connection 60 is attached to the pipe and on la laterally extending leg carries a stop-cock 6|. A second T 62 is connected to the first T and in turn carries a check valve 63 through which air may be drawn into the pipe 55, but may not flow in the opposite direction. Connected to the lateraly extending leg of the T 62 is a pipe 64 which is fitted at its lower end with an elbow 65 attached to a check valve 66. The check valve 66 permits the flow of iiuid into the cylinder but not in an'opposite direction. A pipe connection 61 lis attached to the check valve |56 and extends through the' wall of the cylinder 36 at a point ,where it will be covered on the lower portion of the down stroke of the piston and uncovered for a portion oi the upstroke. of the piston. It is to be understood that the valve 5| connecting with the lower cylinder compartment 51 is a check valve which will allow inow of the uid to the cylinder but will prevent an outilow of fluid. The valve 53 is a Acheckvalve which at all times allows regulated communication between the compartment 51 of the cylinder and the receiving tank This is of considerable importance in the present device ldue to the fact that the pressure -within the compartment 51 of the cylinder and the receiving tank Will be the same, and for the further reason that this arrangement does not cause all of the fluid within the cylinder 36 to be discharged into the receiving tank. Thus there is no tendency to build up heat in the compressor unit, as by this arrangement it will be noted that after the pressure in receiver has reached the pressure at which the compressor is set the same uid is being compressed and expanded as the piston.

reciprocates, The valves and the piping which establishes communication from the pipes 59 to 61 make it possible to supercharge the cylinder as the piston 4| makes an upstroke.

sto'p cock 6|.

In operation of the present invention the required pressure for the receiving tank is determined by the load under which the pumping mechanism is working and by the pressure of iiuid necessary withinthe cylinder 28 to cushion and counterbalance this load and to also aid in lifting the rocking beam I9. The valve 34 may be closed to stop the passage of uid through conduit 33 and the piston 30 to the cylinder 28 if desired. It will be assumed for example that the fluid pressure required is one hundred pounds.

. It will then be evident that the compressor unit This, how. ever, may be optionally done by control of the adjusting the piston rod 40 with relation to the cross head 42 so that the compression space 51 1 within the cylinder will be. such as to produce one hundred pounds pressure as indicated on the gauge 55'. This adjustment is made by regulatingthe sleeve 46 within the cross head to lengthen or shorten the effective length o f the piston rod 40. It will thus be evident that even though the4 pitman rods 44 maintain a constant stroke and that the piston 4| maintains a constant stroke the compression space |51 will be varied in accordance with the adjustment. Under normal conditions it will be assumed that the piston 4| is to create a compression stroke with- 56 will be compressed and forced 'through pipe `5 4 tothe receiving tank Il.

'51 the stop'cock Il is ananas out as action, in which event-the stop cock il is lett open. 'I'hus as the piston moves upwardly toits extreme upper position the port of the pipe Il will be uncovered by the piston 4l and no air will ilow intol the compres-y sion space 5l through the check valve 8B and the pipe 64 by reason oi' the fact that Jno compression `of air can take place above piston Il while valve to the time that the port of- 6I is open. Prior pipe 'B1 is uncovered air will be drawn into'the compression chamber 51 through the check valv 5I and the pipe il. 0n the downstroke oi' the piston Il the check valve 5I will be closed and as the piston Il passes'the port of pipe 81 the compression chamber '51 will be closed against the inilow 'of air and pressure will beimposed upon the entrapped air as itis forced outwardly through the pipel! and the valve 5I and then Upon the next stroke of the piston 4I the procedure 'win be repeated and in the event 1t is desirable to supercharge the iiuid within compression space closed. Thus on a down stroke ofthe piston Il air will be drawn into the displacement space `Il above the piston 4i through check valve Il, pipe connections Il, and l2', and the pipe V59, since on a portion of the down stroke of the piston `4i the port' of pipe Si is closed so that air may be drawn into thel displacement space 56 by suction upon the down stroke of the piston 4I. 0n the. upstroke of piston 4| the check valve has been entrapped within the displacement space l around throughI the pipe and the check valve I8 to the pipe Il. When the the com mud-from the displacement space 56 will be expelled into-the compression space 5l so that the compression space l1 will. not only .contain a knormal volume ot air drawn into it through a predetermined prsure. Upon the down stroke of the piston, Il the. air undery pressure within the space I1 will be furtherv compressed and creed into the receiving. tank through the ilpe Il. Thus here showna multi-stage compression may be tain the num It will'i'urther be .evident that the ar-.- rangement also insures. that while the compressor4 is working the pumping possible toresuisthe apparatus to operate st plessureandto. sure'asadillted means. y

setbvlimpleandeilecve C3 will be closed and the llid which piston Il uncoversthe port otpipe l1 thevalvelibutwillalsocontaln the airfrom the displacementspace II whichisunder' by th arrangement continuously as aa'incident toV tween said second chamber and While Ij have shown the preferred form oi. my invention as nowknown to me it will be understood that various changes might be made in the combination, construction, and arrangement of parts, by those skilled in the art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

' 1. A compressor structure comprising a cylinder closed at one end, a piston within the cylinder, a piston rod connected therewith -and extending from the opposite end of the cylinder, a cylinder head through which said piston reciprocates, and by which ,the opposite end oi' the cylinder is closed, power means'` connected with said piston rod and imparting a stroke of con'- stant length thereto, means for adjusting the piston rod with relation to the power means whereby the compression space between the piston and its opposite head may be varied, means for permitting fluid to be drawn into and expelled from the compression spaces of said cylinder, means for`bypassing the compressed iluid occurrlngin one of said compression chambers 'to the other of said compression chambers before being iinally expelled from the cylinder, and means for controlling said bypass means to establish and interrupt the bypass of fluid from.

one of said compression chambers to the other. 2. A compressor structure, includingl a piston and piston rod, a cylinder in whichsaid pistoh reciprocatesl forming therein compression chambers at opposite sides lof the piston, having closedouter ends through one of which the piston-rod has a slidable bearing, one o! said compression chambers having valved air inlet and outlet connections adjacent its outer end, the said inlet conl nection opening to the atmosphere, a pressure receiver with which the outlet connection communicatesand which? when at a Pressure equaling that otsaid compression chamber. holds the valve of the outlet connection against opening so that the said compression chamber is Vthus closed ,and the same. air therein alternately compressed and expanded as the piston reciprocates. an external i tting on the cylinder forming an air inlet adjacent to the outer end of thelother chamber, a check valve in said htting opening toward the chamber for the inlet of air thereto and the prevention; of out-flow of pressure, a by-pass connection leading from said'ii at a point beto the iirst chamber, a check pass immediately adjacent to A and preventing'back-ilow from said latter valve in said bychamber, said by-p'ass having an outlet to the atmosphere, and a stop valve in said by-pass outlet whereby the by-pass active and inactive as desired.

' masa w. ramon.

said check valve the ilrstchambermay be manually rendered- 

